Abstract
To evaluate the antioxidant effects of β-carotene and astaxanthin, rat liver microsomes were exposed to a mixture of chelated iron (Fe3+/ADP) and NADPH. The carotenoids (190 pmol/mg protein) were incorporated into some of these microsomal membranes, and phospholipid hydroperoxides (PLOOH), thiobarbituric acid reactive substances (TBARS) and endogenous α-tocopherol content were measured over time after the initiation of oxidant stress. In control microsomes, oxidant stress led to accumulation of 1,865 (+/-371) pmol PLOOH/mg protein during the initial 10-min peroxidation reaction, followed by a more gradual increase during the subsequent 20-min of reaction. PLOOH accumulation during the initial 10-min reaction period was reduced to 588 (+/-169) pmol/mg protein with β-carotene present and 800 (+/-288) pmol/mg protein with astaxanthin present. During the following 20-min of incubation, PLOOH levels declined in the carotenoid-supplemented microsomes but continued to increase at a slower rate in control preparations. TBARS did not show such large accumulation as observed in PLOOH during the initial 10-min incubation in any microsomal sample. The presence of carotenoids in the microsomal membrane partially inhibited the loss of α-tocopherol, especially during the later phase of oxidant stress. When lipid peroxidation is generated by membrane-bound cyt-P450, the specific measurement of PLOOH clearly demonstrates that the presence of carotenoids provides antioxidant protection.
Original language | English |
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Pages (from-to) | 345-355 |
Number of pages | 11 |
Journal | Journal of nutritional science and vitaminology |
Volume | 43 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1997 |
Keywords
- Antioxidant
- Astaxanthin
- Lipid peroxidation
- Microsomes
- β-Carotene
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Nutrition and Dietetics